Tree broken at graft union
I thought I saw a branch broken off a tree after a storm, went out, and found my 2 yr old plum tree on the ground, broken off at the graft union. The break didn't look like raw wood at all, it was dark and scabbed over on both the rootstock and the grafted tree. Yet I hadn't noticed anything amiss beforehand.
Is this a common thing? Should I believe I got a badly-grafted tree, or is it just one of those things that happen?